Gen Dent. 2024 Nov-Dec;72(6):38-45.
The purpose of this study was to compare the flexural strength, Weibull modulus (reliability), marginal gap, and internal fit (internal gap) of 4 materials for milling or 3-dimensional (3D) printing of definitive and provisional crowns: IPS e.max CAD (IEC), Paradigm MZ100 Block (PMB), Permanent Crown Resin (PCR), and Temporary CB Resin (TCR). Flexural strength was tested by subjecting sectioned milling blocks (IEC and PMB) or 3D-printed bars (PCR and TCR) to a 3-point bending test in a universal testing machine (n = 15 per material). Crowns were milled or 3D printed, and the marginal gap and internal fit were measured using microcomputed tomography (n = 5 per material). The data were analyzed with a t test and compared using analysis of variance (ANOVA) with Tukey post hoc comparisons (α = 0.05). The groups demonstrated the following mean (SD) flexural strength values: IEC, 335.50 (28.97) MPa; PMB, 154.34 (21.03) MPa; PCR, 128.09 (7.30) MPa; and TCR, 126.29 (9.23) MPa. A 1-way ANOVA revealed significant differences in the flexural strengths of sectioned and 3D-printed bars (P < 0.001). The PMB group showed the lowest Weibull modulus (8.77), indicating its poor reliability. The IEC group showed the smallest marginal gap, 53.42 (31.99) μm; this value was significantly smaller than the gap in the TCR group (P < 0.001) but not the PCR or PMB group. The PMB group had the smallest internal fit discrepancy (87.44 [37.60] μm) but was not significantly different from PCR, while TCR had a significantly greater internal fit discrepancy (130.61 [65.16] μm) than IEC, PMB, and PCR (P < 0.001). The occlusal internal fit discrepancies of 3D-printed crowns were significantly greater than those of milled crowns (P < 0.001). There was no statistically significant difference in flexural strength between the 3D-printed definitive (PCR) and provisional (TCR) materials. When the data were combined according to manufacturing method, the marginal gap and internal fit of crowns fabricated with 3D printing were comparable to those of milled crowns, and all mean marginal gaps were within a clinically acceptable limit of less than 120 μm.
本研究旨在比较 4 种用于制作最终修复体和临时冠的材料的弯曲强度、威布尔模数（可靠性）、边缘间隙和内部适合性（内部间隙）：IPS e.max CAD（IEC）、Paradigm MZ100 块（PMB）、永久性冠树脂（PCR）和临时 CB 树脂（TCR）。将分段铣削块（IEC 和 PMB）或 3D 打印棒（PCR 和 TCR）进行三点弯曲测试，在万能试验机上测试弯曲强度（每种材料各 15 个样本）。制作修复体或 3D 打印冠，使用微计算机断层扫描（micro-computed tomography，micro-CT）测量边缘间隙和内部适合性（每种材料各 5 个样本）。使用 t 检验分析数据，并使用方差分析（analysis of variance，ANOVA）和 Tukey 事后比较进行比较（α=0.05）。各组的平均（标准差）弯曲强度值如下：IEC，335.50（28.97）MPa；PMB，154.34（21.03）MPa；PCR，128.09（7.30）MPa；TCR，126.29（9.23）MPa。单因素方差分析显示分段和 3D 打印棒的弯曲强度存在显著差异（P < 0.001）。PMB 组的威布尔模数最低（8.77），表明其可靠性较差。IEC 组的边缘间隙最小，为 53.42（31.99）μm；与 TCR 组相比，该值显著更小（P < 0.001），但与 PCR 或 PMB 组无显著差异。PMB 组的内部拟合差异最小（87.44[37.60]μm），但与 PCR 无显著差异，而 TCR 的内部拟合差异显著大于 IEC、PMB 和 PCR（P < 0.001）。3D 打印冠的牙合面内部拟合差异显著大于铣削冠（P < 0.001）。3D 打印最终修复体（PCR）和临时（TCR）材料的弯曲强度无统计学差异。根据制造方法合并数据后，3D 打印制作的冠的边缘间隙和内部适合性与铣削冠相当，所有平均边缘间隙均在临床可接受的小于 120μm 范围内。
